| Message ID | 20180803002220.20810-1-fw@strlen.de |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next,v3] ipv6: defrag: drop non-last frags smaller than min mtu | expand |
From: Florian Westphal <fw@strlen.de> Date: Fri, 3 Aug 2018 02:22:20 +0200 > don't bother with pathological cases, they only waste cycles. > IPv6 requires a minimum MTU of 1280 so we should never see fragments > smaller than this (except last frag). > > v3: don't use awkward "-offset + len" > v2: drop IPv4 part, which added same check w. IPV4_MIN_MTU (68). > There were concerns that there could be even smaller frags > generated by intermediate nodes, e.g. on radio networks. > > Cc: Peter Oskolkov <posk@google.com> > Cc: Eric Dumazet <edumazet@google.com> > Signed-off-by: Florian Westphal <fw@strlen.de> Applied, thanks Florian.
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c index 0610bdab721c..aed9766559c9 100644 --- a/net/ipv6/netfilter/nf_conntrack_reasm.c +++ b/net/ipv6/netfilter/nf_conntrack_reasm.c @@ -557,6 +557,10 @@ int nf_ct_frag6_gather(struct net *net, struct sk_buff *skb, u32 user) hdr = ipv6_hdr(skb); fhdr = (struct frag_hdr *)skb_transport_header(skb); + if (skb->len - skb_network_offset(skb) < IPV6_MIN_MTU && + fhdr->frag_off & htons(IP6_MF)) + return -EINVAL; + skb_orphan(skb); fq = fq_find(net, fhdr->identification, user, hdr, skb->dev ? skb->dev->ifindex : 0); diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c index 6edd2ac8ae4b..a976b143463b 100644 --- a/net/ipv6/reassembly.c +++ b/net/ipv6/reassembly.c @@ -455,6 +455,10 @@ static int ipv6_frag_rcv(struct sk_buff *skb) return 1; } + if (skb->len - skb_network_offset(skb) < IPV6_MIN_MTU && + fhdr->frag_off & htons(IP6_MF)) + goto fail_hdr; + iif = skb->dev ? skb->dev->ifindex : 0; fq = fq_find(net, fhdr->identification, hdr, iif); if (fq) {
don't bother with pathological cases, they only waste cycles. IPv6 requires a minimum MTU of 1280 so we should never see fragments smaller than this (except last frag). v3: don't use awkward "-offset + len" v2: drop IPv4 part, which added same check w. IPV4_MIN_MTU (68). There were concerns that there could be even smaller frags generated by intermediate nodes, e.g. on radio networks. Cc: Peter Oskolkov <posk@google.com> Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> --- net/ipv6/netfilter/nf_conntrack_reasm.c | 4 ++++ net/ipv6/reassembly.c | 4 ++++ 2 files changed, 8 insertions(+)